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system: Introduce 'file-systems' Shepherd service.

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* gnu/services/base.scm (file-system-shepherd-services): New procedure.
(file-system-service-type): Use it as the SHEPHERD-ROOT-SERVICE-TYPE
extension.
(user-processes-service-type): Change to take a single 'grace-delay'
parameter.
(user-processes-service): Remove 'file-systems' parameter.  Pass
GRACE-DELAY as the only value for the service.
* gnu/system.scm (essential-services): Adjust accordingly.
This commit is contained in:
Ludovic Courtès 2017-01-31 22:53:29 +01:00
parent 2fe4ceee18
commit a43aca973e
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2 changed files with 84 additions and 76 deletions
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155
gnu/services/base.scm
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@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015, 2016 Alex Kost <alezost@gmail.com>
;;; Copyright © 2015, 2016 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2015 Sou Bunnbu <iyzsong@gmail.com>
@ -313,13 +313,26 @@ FILE-SYSTEM."
#:select (mount-file-system))
,@%default-modules)))))))
(define (file-system-shepherd-services file-systems)
"Return the list of Shepherd services for FILE-SYSTEMS."
(let* ((file-systems (filter file-system-mount? file-systems)))
(define sink
(shepherd-service
(provision '(file-systems))
(requirement (cons* 'root-file-system 'user-file-systems
(map file-system->shepherd-service-name
file-systems)))
(documentation "Target for all the initially-mounted file systems")
(start #~(const #t))
(stop #~(const #f))))
(cons sink (map file-system-shepherd-service file-systems))))
(define file-system-service-type
(service-type (name 'file-systems)
(extensions
(list (service-extension shepherd-root-service-type
(lambda (file-systems)
(filter-map file-system-shepherd-service
file-systems)))
file-system-shepherd-services)
(service-extension fstab-service-type
identity)))
(compose concatenate)
@ -366,93 +379,89 @@ in KNOWN-MOUNT-POINTS when it is stopped."
(define user-processes-service-type
(shepherd-service-type
'user-processes
(match-lambda
((requirements grace-delay)
(shepherd-service
(documentation "When stopped, terminate all user processes.")
(provision '(user-processes))
(requirement (cons* 'root-file-system 'user-file-systems
(map file-system->shepherd-service-name
requirements)))
(start #~(const #t))
(stop #~(lambda _
(define (kill-except omit signal)
;; Kill all the processes with SIGNAL except those listed
;; in OMIT and the current process.
(let ((omit (cons (getpid) omit)))
(for-each (lambda (pid)
(unless (memv pid omit)
(false-if-exception
(kill pid signal))))
(processes))))
(lambda (grace-delay)
(shepherd-service
(documentation "When stopped, terminate all user processes.")
(provision '(user-processes))
(requirement '(file-systems))
(start #~(const #t))
(stop #~(lambda _
(define (kill-except omit signal)
;; Kill all the processes with SIGNAL except those listed
;; in OMIT and the current process.
(let ((omit (cons (getpid) omit)))
(for-each (lambda (pid)
(unless (memv pid omit)
(false-if-exception
(kill pid signal))))
(processes))))
(define omitted-pids
;; List of PIDs that must not be killed.
(if (file-exists? #$%do-not-kill-file)
(map string->number
(call-with-input-file #$%do-not-kill-file
(compose string-tokenize
(@ (ice-9 rdelim) read-string))))
'()))
(define omitted-pids
;; List of PIDs that must not be killed.
(if (file-exists? #$%do-not-kill-file)
(map string->number
(call-with-input-file #$%do-not-kill-file
(compose string-tokenize
(@ (ice-9 rdelim) read-string))))
'()))
(define (now)
(car (gettimeofday)))
(define (now)
(car (gettimeofday)))
(define (sleep* n)
;; Really sleep N seconds.
;; Work around <http://bugs.gnu.org/19581>.
(define start (now))
(let loop ((elapsed 0))
(when (> n elapsed)
(sleep (- n elapsed))
(loop (- (now) start)))))
(define (sleep* n)
;; Really sleep N seconds.
;; Work around <http://bugs.gnu.org/19581>.
(define start (now))
(let loop ((elapsed 0))
(when (> n elapsed)
(sleep (- n elapsed))
(loop (- (now) start)))))
(define lset= (@ (srfi srfi-1) lset=))
(define lset= (@ (srfi srfi-1) lset=))
(display "sending all processes the TERM signal\n")
(display "sending all processes the TERM signal\n")
(if (null? omitted-pids)
(begin
;; Easy: terminate all of them.
(kill -1 SIGTERM)
(sleep* #$grace-delay)
(kill -1 SIGKILL))
(begin
;; Kill them all except OMITTED-PIDS. XXX: We would
;; like to (kill -1 SIGSTOP) to get a fixed list of
;; processes, like 'killall5' does, but that seems
;; unreliable.
(kill-except omitted-pids SIGTERM)
(sleep* #$grace-delay)
(kill-except omitted-pids SIGKILL)
(delete-file #$%do-not-kill-file)))
(if (null? omitted-pids)
(begin
;; Easy: terminate all of them.
(kill -1 SIGTERM)
(sleep* #$grace-delay)
(kill -1 SIGKILL))
(begin
;; Kill them all except OMITTED-PIDS. XXX: We would
;; like to (kill -1 SIGSTOP) to get a fixed list of
;; processes, like 'killall5' does, but that seems
;; unreliable.
(kill-except omitted-pids SIGTERM)
(sleep* #$grace-delay)
(kill-except omitted-pids SIGKILL)
(delete-file #$%do-not-kill-file)))
(let wait ()
(let ((pids (processes)))
(unless (lset= = pids (cons 1 omitted-pids))
(format #t "waiting for process termination\
(let wait ()
(let ((pids (processes)))
(unless (lset= = pids (cons 1 omitted-pids))
(format #t "waiting for process termination\
(processes left: ~s)~%"
pids)
(sleep* 2)
(wait))))
pids)
(sleep* 2)
(wait))))
(display "all processes have been terminated\n")
#f))
(respawn? #f))))))
(display "all processes have been terminated\n")
#f))
(respawn? #f)))))
(define* (user-processes-service file-systems #:key (grace-delay 4))
(define* (user-processes-service #:key (grace-delay 4))
"Return the service that is responsible for terminating all the processes so
that the root file system can be re-mounted read-only, just before
rebooting/halting. Processes still running GRACE-DELAY seconds after SIGTERM
has been sent are terminated with SIGKILL.
The returned service will depend on 'root-file-system' and on all the shepherd
services corresponding to FILE-SYSTEMS.
The returned service will depend on 'file-systems', meaning that it is
considered started after all the auto-mount file systems have been mounted.
All the services that spawn processes must depend on this one so that they are
stopped before 'kill' is called."
(service user-processes-service-type
(list (filter file-system-mount? file-systems) grace-delay)))
(service user-processes-service-type grace-delay))
;;;

5
gnu/system.scm
View file

@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2015, 2016 Alex Kost <alezost@gmail.com>
;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
@ -293,8 +293,7 @@ a container or that of a \"bare metal\" system."
(other-fs (non-boot-file-system-service os))
(unmount (user-unmount-service known-fs))
(swaps (swap-services os))
(procs (user-processes-service
(service-parameters other-fs)))
(procs (user-processes-service))
(host-name (host-name-service (operating-system-host-name os)))
(entries (operating-system-directory-base-entries
os #:container? container?)))